module led_matrix (
	input sys_clk, 
	input sys_rst, 
	input [3:0] key_id,
	output reg [3:0] led);

reg [3:0] led_value;

always @(posedge sys_clk or negedge sys_rst) begin
	if (!sys_rst) begin
		led_value <= 4'b0000;
		led <= led_value;
	end
	else													begin
		if (key_id != 0) 								begin
			led_value = 4'b01 << (key_id - 1);
			led <= led_value;
		end
		else												begin
			led <= 4'b0000;
		end
	end

end

endmodule